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This preliminary investigation addresses key program elements for sonar sensing in a shallow-water environment to establish
bounds on possible solutions and to reduce program uncertainty. The modeling and experimental program focuses on two
issues - the potential degradation of sonar data due to signal masking by shallow-water reverberation and signal loss caused by
extreme platform motions. The research program combines theoretical analysis, experimental validation in a shallow-water
environment, and development of a computer model to explore parametric sensitivity. Results from an initial dock-side test show
good agreement with the theoretical predictions. From the shallow-water experiments and acoustic modeling we conclude that: (1)
Signal motion loss can influence the reverberation level significantly but is not the dominant factor in target detection for sonars
in the frequency range of interest (>200 kHz); a high-quality (velocity-aided) inertial navigation and attitude system will be
sufficient to correct for geometric distortions caused by platform motion. (2) Although surface reverberation and multipath noise
can be a factor, partcularly in shadow-mode imaging, reverberation levels are rapidly attenuated at the frequencies of interest and
beam patterns can be manipulated to reject most interferences; echo-mode imaging is still dominated by the contrast between target
strength and bottom reverberation.

In the northern Gulf of Mexico, a series of seafloor mounds lie along the floor of the Mississippi Canyon in Atwater Valley lease blocks 13 and 14. The mounds, one of which was drilled by the Chevron Joint Industry Project ...

Sound propagation in shallow water is highly dependent on the interaction of the
sound field with the bottom. In order to fully understand this problem, it is necessary
to obtain reliable estimates of bottom geoacoustic ...

Low frequency acoustic propagation in shallow water is examined from a normal
mode context. By modelling the far field pressure field as a modal sum, propagating mode
characteristics of wavenumber, initial phase, attennation ...

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